Tools
Web Search and Exa Search
Two ways to pull outside material into a run, and which one suits which question.
Two of the four retrieval switches reach outside RTLBridge. They answer different kinds of question, and turning both on at once is rarely useful.
Web Search
Web Search runs your description through a search-capable model before generation starts and passes what it finds along as context. It is the right tool when the answer exists on a page somewhere and you would otherwise go and look it up yourself.
Good uses:
- Register maps and pin behaviour for a specific part.
- Timing requirements for a peripheral you are talking to.
- The exact framing of a protocol you half-remember.
- Errata and known quirks of a device family.
Note
Search results are context, not gospel. Anything it finds still has to survive the testbench, and a wrong page produces a confidently wrong module. If you already know the numbers, put them in the spec instead; that is both faster and more reliable.
Exa Search
Exa searches by meaning rather than by keyword, and it is tuned toward technical documents: datasheets, standards, application notes, papers. It returns passages rather than links, so the run gets the relevant paragraph instead of a page to guess at.
Good uses:
- Standards work: AXI, AHB, I2C, SPI, Ethernet framing, PCIe basics.
- A design technique you can describe but cannot name.
- Comparing how a problem is usually solved before committing to an approach.
Which one to use
| Question | Tool |
|---|---|
| What is the reset value of register 0x1C on this chip? | Web Search |
| How is a CRC-32 usually pipelined for a 64-bit datapath? | Exa Search |
| What baud rate divisors does this dev board use? | Web Search |
| What does the AXI spec say about WLAST on a single-beat write? | Exa Search |
Cost and time
Both add a step before generation, so a run takes longer. Neither counts as a separate run against your allowance; the search happens inside the run you already started. On the free tier, where runs settle at measured cost, a search makes the run a little more expensive.
If Exa is greyed out
Exa needs an API key configured on the deployment. If the switch does nothing or the run reports no results, that integration is not enabled where you are running; Web Search is the fallback and needs no extra configuration.